# Department of the Army- SDDC — Hazardous Materials Safety Interpretation **Citation:** 11-0173 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2011-09-01 11-0173 response to Department of the Army- SDDC concerning 176.144, 176.170, 176.83. ## Document text <<>> U.S. Department of Transportation 1200 New Jersey Avenue, SE Washington, DC 20590 Pipeline and Hazardous Materials Safety Administration SEP 0 1 2011 Mr. Daniel A. Maham Director of Safety Department of the Army- SDDC 1 Solider Way, Bldg 1900W Scott AFB, IL 62225 Reference No.: 11-0173 Dear Mr. Maham: This responds to your July 25, 2011 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the on deck segregation of freight containers carrying incompatible explosives in accordance with § 176.144(a). In particular, you ask if these freight containers must be segregated 20 ft (6m) fore and aft and 8 feet (25m) athwartship from each other in accordance with § 176.170(f) or 20 feet (6m) from each other in all directions in accordance with § 176.144(e). Freight containers carrying incompatibJe explosives must be segregated in accordance with § 176.170(f) and 176.83(f) or 176.83(1)(3), as appropriate. Section 176.144(e) does not apply to the segregation of incompatible explosives in separate freight containers. Although not specifically stated, § 176.144(e) only applies to the segregation of individual packages, pallets, or magazines containing incompatible explosives when on deck. I hope this satisfies your inquiry. Please contact us if we can be of further assistance. Delmer Bi~./#- Senior Regulations Advisor, Standards Development Branch Standards and Rulemaking Division <<>> DEPARTMENT OF THE ARMY MILITARY SURFACE DEPLOYMENT AND DISTRIBUTION COMMAND 1 SOLDIER WAY, BLDG 1900W SCOTT AFB, IL 62225·5006 REPLY TO ATIENTIONOF July 25,2011 Directorate of Safety (AMSSD-SA)· Office of Hazardous Materials Standards, Pipeline and Hazardous Materials Safety Administration ATTN: PHH-IO US Department ofTransportation, East Building 1200 New Jersey Avenue, SE Washington, DC 20590-0001 Dear Madam/Sir: In accordance with the' provisions ofTitle 49, Code ofFederal Regulations (CFR), Part 105, Section 105.20, the Department of Defense (DOD) hereby requests an Interpretation of the Hazardous Materials Regulations as outlined below. DOD petitions for a clarification of contrasting information from standard numbers 49 CFR 176.144 and 49 CFR 176.170. The following file number is assigned: File Number: 54-11 (0721) Re: Request Interpretation of 49 CFR 176.144, Segregation of Class I (explosive) materials and 49 CFR 176.170, Transport of Class I (explosive) materials. Proponent: Department ofDefense (DoD) This question pertains to the regulations concerning segregation ofHazardous Material Class 1 stored on container ships. Standard number 49 CFR 176.144(e) states that, "When Class 1 (explosive) materials of different compatibility groups are carried on deck, they must be stored not less than 6 m (20 ft) apart unless they are allowed under Table 176. 144(a) to be stowed in the same compartment, magazine, or cargo transport unit." On the other hand, standard number 49 CFR 176.170(1), which specifically addresses Class 1 shipment in freight container units, requires that such freight containers be separated from each other in accordance with Table 176.83(1), which in this case requires one container space fore, aft, and athwartships. The container space is then defmed in standard number 49 CFR 176.83(1)(4) as 6m (20 ft) fore and aft, and 2.5 m (8ft) athwartships. While both standards refer to the storage ofClass 1 materials that are incompatible in accordance with Table 176.144(a), the standard that directly covers freight container storage of Class I material designates specific distances in three directions, rather than the general distance for Class I in all types of Class 1 storage. Does then, incompatible Class 1 material as defmed by Table 176.144(a), stored in freight containers, follow the separation requirements of standard number 49 CFR 176.170 (6 m (20 ft) fore and aft, and 2.5 m (8 ft) athwartships) or standard number 49 CFR 176.144 (6 m (20 ft) in an directions)? The point ofcontact for this organization is Mr. Tom Briggs. He can be reached via mail, at (618) 2205039, or at Thomas.h.briggs@us.army.mil. Thankyou for your time in this matter and we look forward to your rapid response. Sincerely, ~. ;/Je .#!~, Danie~~m Director of Safety ____ Printed on • Recycled Paper ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `12892425634e7b38372c7ad65a30b30549f797f11a70ae9b4b32ed6f4e490b9f` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-22T13:20:06.959Z - Document slug: `phmsa-interpretation-11-0173` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Department of the Army- SDDC" ], "individuals": [ "Mr. Daniel A. 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